Video-based Learning Versus Traditional Method for Preclinical Course of Complete Denture Fabrication.

STATEMENT OF THE PROBLEM
Advances in computer science and technology allow the instructors to use instructional multimedia programs to enhance the process of learning for dental students.


PURPOSE
The purpose of this study was to determine the effect of a new educational modality by using videotapes on the performance of dental students in preclinical course of complete denture fabrication.


MATERIALS AND METHOD
This quasi-experimental study was performed on 54 junior dental students in Shahid Beheshti University of Medical Sciences (SBMU). Twenty-five and 29 students were evaluated in two consecutive semesters as controls and cases, respectively for the same course. The two groups were matched in terms of "knowledge about complete denture fabrication" and "basic dental skills" using a written test and a practical exam, respectively. After the intervention, performance and clinical skills of students were assessed in 8 steps. Eventually, a post-test was carried out to find changes in knowledge and skills of students in this regard.


RESULTS
In the two groups with the same baseline level of knowledge and skills, independent T-test showed that students in the test group had a significantly superior performance in primary impression taking (p= 0.001) and primary cast fabrication (p= 0.001). In terms of anterior teeth set up, students in the control group had a significantly better performance (p= 0.001).


CONCLUSION
Instructional videotapes can aid in teaching fabrication of complete denture and are as effective as the traditional teaching system.

ture-based) and CAL. However, it has been suggested that CAL may successfully replace traditional learning strategies. [7] Some studies consider e-courses or elearning as a supplement or complement to traditional teaching methods. [8][9] Several studies discussed the advantages of this new educational system and reported that this system can be an additional resource for students, [10] may help in instruction of fixed prosthodontics, [11] assist students in developing skills more efficiently, [12][13] as well as having a significant impact on skills scores of students. [14] Other studies revealed that a higher percentage of students preferred e-learning and had a positive perception towards it. [15][16][17][18] In another study, the computer-assisted and computerassisted plus text-based learning groups gained significantly more knowledge than the text-based learning group. [19] However, controversy still exists in this respect.
For instance, one study reported significantly higher learning retention in trainees through lecturing rather than e-learning. [20] A study by Walmsley et al. indicated differences in attitudes of the staff and students towards the use of internet as a resource for dental education. [21] Another study showed that dentists, similar to dental students, disliked reading electronic textbooks. [22] Responses to the survey revealed some disagreements between administrators and information technology specialists. [23] Application of new technology to promote learning in academic contexts is rapidly growing and relevant experiences of researchers and the results of research projects should be incorporated in the educational curriculum. E-curriculum planners should pay close attention to implementation problems, [24] and distance learning should be organized with a mixture of audio and video input. [25] However, it has been suggested that CAL should not replace traditional education. [26] Clearly, this topic needs further scrutiny in complex theoretical and practical (clinical) contents.
Complete denture fabrication is a lengthy preclinical course in undergraduate dental curriculum covering all phases of denture fabrication from primary impression to finishing and polishing. Under these circumstances, it seems necessary to analyze and compare the students' skills between the two groups in every step of the procedure. Studies comparing the results of different instruction techniques in this respect are scarce and to the best of our knowledge, no study has compared scores gained by students from each phase of fabrication in the two groups of conventional and multimedia instruction.
The purpose of this study was to assess and compare the effectiveness of standard lecture with computer assisted learning using an educational CD ROM developed for preclinical course of denture fabrication at the School of Dentistry, SBMU. The aim was to clearly demonstrate differences or similarities between the two groups in each stage of practical course from primary impression to complete arrangement of teeth.

Materials and Method
This quasi-experimental study was conducted on 54 students in two consecutive semesters at School of Dentistry, SBMU. Twenty-five students in the first semester and 29 students in the second semester were evaluated as controls and cases, respectively. No age or sex limit was set. The understudy subjects all had taken the preclinical complete denture fabrication course.
The traditional educational content included familiarization of students with the materials and instruments used in the complete denture preclinical course for fabrication of a complete denture set including primary impression taking, fabrication of primary cast, fabrication of special tray, border molding, final impression taking, master cast, record base and wax rim fabrication, mounting the master casts on the articulator, and anterior and posterior teeth set up. The traditional course was held during 30 sessions. In the conventional classroom learning, two instructors from removable prosthodontics department trained the students. The trainees could consult their instructors during the two sessions that were held twice a week if they had any problem.
In the new experimental method, all the abovementioned steps were taught to the students with the use of videotapes and other supplemental educational tools.
The process of learning in this method was supervised by an instructor and a technician working in the removable prosthodontics department. All students in the test group had access to a personal computer in the class and watched the related videotapes throughout the sessions.
Instructors also participated in these sessions. Similar to conventional learning, 30 sessions were held. It should be mentioned that students had to practice only during the sessions and were not allowed to take their work out 23 of the class.

Assessment of the baseline knowledge of subjects
Since students from two different classes were selected as the case and control groups, at the beginning we had to make sure that the two groups had the same level of baseline knowledge about complete denture fabrication. Therefore, at baseline, a written exam (exam I) was taken from students in both groups containing 10 questions. The reliability of the exam was approved by a faculty member of School of Dentistry, SBMU. The students in both groups were given ten minutes to answer the questions. By doing so, the two groups were matched in terms of their baseline information regarding this topic.

Assessment of practical skills
In order to evaluate and compare the practical skills of students in the two groups, a practical dental anatomy exam was held (exam II) that included carving a maxillary canine tooth out of a wax block. Assessment of the scores of exam II was done by one of the operative dentistry faculty members.

Assessment of level of knowledge about the complete denture fabrication
In the next phase, in order to assess the knowledge of students in both groups about complete denture fabrication before the initiation of the preclinical course, a written exam was taken containing 9 questions. The reliability of the test had been confirmed by a group of faculty members (exam III, pretest). Students had 10 minutes to answer the questions.

Educational methods
For the first group of students (control group), teaching was performed traditionally by instructors in all steps and demonstrations of each step were done in form of live teaching. For the second group of students (case group), teaching was done based on multimedia educational system (that had been prepared in advance) by using a CD. The CD was prepared by the prosthodontics faculty members (removable section) and included teaching of A-Z steps of complete denture fabrication on a model. This score sheet was considered as exam IV. It should be mentioned that reviewers who assessed the abovementioned phases were blinded to the study.

Assessment of the final knowledge of students about complete denture fabrication
After completion of the course in the two groups, a written exam was held with 23 questions (exam V) in order to assess and compare the changes in knowledge of students in the two groups. The reliability of the test was confirmed by faculty members of the department of removable prosthodontics. Two tests were held separately for each group and the students were supposed to answer the questions in 35 minutes.
The quality of third and fifth exams had to be assessed in terms of level of difficulty. Thus, 10 senior students that had a GPA score over 3.5 were selected to take the exams. They were given the same time periods (as the test and control groups) to answer the questions   Figure 1).

Discussion
Advancements in science and technology now allow for the application of multimedia in educational curricula. [12,27] In this study, a multimedia courseware package in preclinical complete denture fabrication was devel- Since in this study the test and control groups were from different educational years, for matching the groups, three pre-tests were held to determine the students' baseline knowledge, and practical skills in general and about complete denture fabrication in particular. This phase had been skipped in many similar studies.
Naturally, students have different learning abilities and the instruction system should be available for all students with different abilities. Qayumi et al. [19] in their study on two medical universities evaluated the efficacy of three different educational modalities: computer-assisted, text-based, and a combination of both learning systems. Comparison of 2 control and 3 test groups revealed significant improvement in learning of students. In terms of knowledge measure, progress of students in the computer-assisted and computer and text learning was significantly higher than that of the students in text-based group. Learning of students with better educational background was independent of the study method, but students with poorer scores showed a better learning after using computer. In the mentioned study, the students' baseline knowledge in the 4 groups was not assessed. In a study by Ludlow and Platin, [16] a modified crossover design was used to reduce the confounding effect of different baseline knowledge levels of students. Aly et al. [2] changed the groups at the end of semester and tried to reduce this effect. In another study, Abutarbush et al. [18] [28] about two-thirds of the students under e-teaching found college e-resources effective for learning but they preferred printed text and liked e-teaching as a supplement, not as a replacement for traditional lectures. These findings convinced the authors of the current study to use elearning as a complimentary method to enhance dental education.
Obviously, having baseline knowledge about a topic can better prepare students for an educational video on that specific subject. Brownel et al. [20] compared lecture and e-learning in new graduates and experienced dental professionals and found that e-learning was more effective in experienced dental professionals while the situation was reverse for new graduates. In terms of maintaining the gained knowledge, Stern et al. [14] revealed that the students' knowledge level decreased one year after the intervention but the skills did not. Equipping the educational environment with hightech teaching devices can further encourage and engage students in educational activities, for instance, holding conferences and seminars can improve their clinical performance. This study showed that many students generally liked e-learning and it seems that it could be more effective when combined with face-to-face teaching. Comprehensive clinical education increases the number of skilled dentists offering better health care services to the public. However, similar studies with a larger sample size are required to generalize the results.
Furthermore, in this study, the students had access to the video only during the classroom sessions. Thus, in future studies, it is recommended to provide students the chance of constant access to the educational videos through the e-learning courses.

Conclusion
Within the limitations of this study, instructional films could be successfully used to reduce the need for constant presence of mentors or as a complement to the traditional educational systems in preclinical course of complete denture fabrication. The instructional multimedia was as effective as the traditional learning system, although traditional learning group performed significantly better than the test group in terms of anterior teeth set up.